The present invention relates to a method and a processing unit for determining the position of the armature of a synchronous machine relative to the stator of said synchronous machine.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
The prior art discloses numerous methods by which the position of the armature of a synchronous machine can be determined. Many of these methods are based on costly measurements of the inductivities of the primary circuit coils, or on the measurement and analysis of the electromotive counterforce. Such methods allow a synchronous machine to be operated entirely without a position measuring device.
In the present document, the term synchronous machine is understood to include linear synchronous machines, rotor-based synchronous machines, separately excited synchronous machines and self-excited synchronous machines. The term synchronous machine includes all machines in which the armature field moves synchronously relative to the stator field, and therefore brushless direct-current motors and electronically commuted motors are also covered by the term synchronous machine. If a current vector is specified, in the phasor diagram it has the magnitude of the space phasor, which was calculated on the basis of the impressed currents, and the direction of the space phasor. All of the angle data relating to the armature of the synchronous machine relates in the following to an electric period, i.e. to a complete rotation of the current vector. For example, a complete rotation of the motor shaft can correspond to a plurality of electric periods in a rotor-based synchronous machine. This applies in particular if the number of poles is greater than one.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide an improved method for determining the position of the armature of a synchronous machine relative to the stator of the synchronous machine.